Method for making moisture-permeable waterproof shoe having integrally formed upper

ABSTRACT

A method for making a moisture-permeable waterproof shoe includes: (A) sleeving an inner sleeve unit on a last; (B) coating a bonding agent on an inner surface of an upper unit; (C) sleeving the upper unit on an assembly of the inner sleeve unit and the last; (D) placing an assembly of the upper unit, the inner sleeve unit and the last in a heating device; (E) placing the assembly in a vacuum bag; (F) placing the vacuum bag in a freezing device; (G) removing the assembly from the vacuum bag; (H) pulling out the last from the inner sleeve unit; and (I) fixing a sole to a bottom portion of a three-dimensional upper structure.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwanese Patent Application No.110114712, filed on Apr. 23, 2021.

FIELD

The disclosure relates to a shoe, more particularly to a method formaking a moisture-permeable waterproof shoe having an integrally formedupper.

BACKGROUND

Referring to FIGS. 1 and 2, a conventional shoe is generally made byfirst sewing together an upper 1 and a midsole cardboard 2 to form athree-dimensional (3D) upper structure 3, after which a last 4 isinserted into an interior space 301 of the 3D upper structure 3, andfinally, a sole 4 is adhered to the 3D upper structure 3, therebyforming the conventional shoe.

However, to sew together the upper 1 and the midsole cardboard 2 havingdifferent materials is labor-intensive. Further, the conventional shoehas many components, so that the manufacturing cost thereof isincreased. Moreover, the interior space 301 has a volume exactlycorresponding to a volume of the last 4 that is inserted therein. Afterthe last 4 is pulled out from the upper, the volume of the 3D upperstructure 3 will remain corresponding to the size of the last 4 and willnot shrink, so that the conventional shoe does not cover well a foot ofa user during wear thereof, and is thus uncomfortable to wear.

SUMMARY

Therefore, an object of the present disclosure is to provide a methodfor making a moisture-permeable waterproof shoe having an integrallyformed upper that is capable of alleviating at least one of thedrawbacks of the prior art.

Accordingly, a method for making a moisture-permeable waterproof shoe ofthis disclosure includes:

(A) sleeving a shoe-shaped inner sleeve unit, which ismoisture-permeable and waterproof and which defines a foot space havinga top open end, on a forming portion of a last such that the formingportion of the last is inserted into the foot space through the top openend thereof, the foot space having a volume smaller than a formingvolume of the forming portion by 5 to 10%;

(B) coating a bonding agent on an inner surface of an upper unit whichdefines an interior space having a top open end;

(C) sleeving the upper unit on an assembly of the shoe-shaped innersleeve unit and the last such that the assembly of the shoe-shaped innersleeve unit and the last is inserted into the interior space through thetop open end thereof, the interior space having a volume smaller thanthe forming volume of the forming portion by 5 to 10%;

(D) placing an assembly of the upper unit, the shoe-shaped inner sleeveunit and the last in a heating device to heat the assembly of the upperunit, the shoe-shaped inner sleeve unit and the last to a predeterminedheating temperature and a predetermined heating time;

(E) removing the assembly of the upper unit, the shoe-shaped innersleeve unit and the last from the heating device, and then placing theassembly of the upper unit, the shoe-shaped inner sleeve unit and thelast in a vacuum bag, after which air is evacuated from the vacuum bagfor a predetermined vacuum time;

(F) placing the vacuum bag, which contains the assembly of the upperunit, the shoe-shaped inner sleeve unit and the last, in a freezingdevice to freeze the vacuum bag to a predetermined freezing temperatureand a predetermined freezing time;

(G) removing the vacuum bag from the freezing device, and then removingthe assembly of the upper unit, the shoe-shaped inner sleeve unit andthe last from the vacuum bag;

(H) pulling out the last from the shoe-shaped inner sleeve unit, theupper unit and the shoe-shaped inner sleeve unit forming athree-dimensional moisture-permeable waterproof upper structure afterthe last is pulled out; and

(I) fixing a sole to a bottom portion of the three-dimensionalmoisture-permeable waterproof upper structure.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the disclosure will become apparent inthe following detailed description of the embodiment with reference tothe accompanying drawings, of which:

FIG. 1 is an exploded perspective view of an upper and a midsolecardboard of a conventional shoe and a last;

FIG. 2 is an assembled sectional view of FIG. 1;

FIGS. 3A and 3B are flow charts, illustrating the steps involved in amethod for making a moisture-permeable waterproof shoe according to anembodiment of the present disclosure;

FIG. 4 is an enlarged fragmentary sectional view of an inner sleeve basematerial used by the embodiment;

FIG. 5 is a fragmentary perspective view of the inner sleeve basematerial, illustrating how the inner sleeve base material is cut to forman inner sleeve cut piece;

FIG. 6 is a perspective view of the inner sleeve cut piece;

FIG. 7 illustrates how the inner sleeve cut piece is sewn to form ashoe-shaped inner sleeve;

FIG. 8 is a view similar to FIG. 7, but illustrating a plurality ofwaterproof strips being fixedly connected to an outer surface of theshoe-shaped inner sleeve so as to cover the seams thereof and form ashoe-shaped inner sleeve unit;

FIG. 9 is a perspective view of an upper cut piece used by theembodiment;

FIG. 10 illustrates how the upper cut piece is folded to form an upperunit;

FIG. 11 illustrates how the cut piece is sewn to form the upper unit;

FIG. 12 is a bottom view of the upper unit;

FIG. 13 is a perspective view of an assembly of the shoe-shaped innersleeve unit and a last;

FIG. 14 illustrates an inner surface of the upper unit being sprayedwith adhesive;

FIG. 15 is a view similar to FIG. 13, but with the upper unit beingsleeved on the assembly of the shoe-shaped inner sleeve unit and thelast;

FIG. 16 illustrates an assembly of the upper unit, the shoe-shaped innersleeve unit and the last being placed in a heating device;

FIG. 17 illustrates the assembly of the upper unit, the shoe-shapedinner sleeve unit and the last being placed in a vacuum bag;

FIG. 18 illustrates the vacuum bag containing the assembly of the upperunit, the shoe-shaped inner sleeve unit and the last being placed in afreezing device;

FIG. 19 illustrates the assembly of the upper unit, the shoe-shapedinner sleeve unit and the last after being removed from the vacuum bag;

FIG. 20 illustrates the shoe-shaped inner sleeve unit and the upper unitforming a three-dimensional moisture-permeable waterproof upperstructure after the last is pulled out from the shoe-shaped inner sleeveunit;

FIG. 21 illustrates two decorative tightening plates being fixedlydisposed on left and right sides of a sole, after which the sole isfixedly connected to a bottom portion of the three-dimensionalmoisture-permeable waterproof upper structure;

FIG. 22 is a sectional view of an assembly of three-dimensionalmoisture-permeable waterproof upper structure and the last;

FIG. 23 is a view similar to FIG. 22, but with the last being pulled outfrom the three-dimensional moisture-permeable waterproof upperstructure;

FIG. 24 is an enlarged fragmentary view of FIG. 23;

FIG. 25 is a perspective view of the moisture-permeable waterproof shoemade from the method of this embodiment; and

FIG. 26 is an exploded perspective view of the moisture-permeablewaterproof shoe of FIG. 25 and the last.

DETAILED DESCRIPTION

Referring to FIGS. 3A and 3B, a method for making a moisture-permeablewaterproof shoe 100 according to an embodiment of the present disclosureincludes the following steps:

Step 700: adhering a moisture-permeable waterproof membrane 310 to athree-layer fabric 320 to form an inner sleeve base material 300, asshown in FIG. 4. The three-layer fabric 320 includes a fabric lininglayer 321, an outer fabric layer 322, and a foam layer 323 fixed betweenthe fabric lining layer 321 and the outer fabric layer 322. Themoisture-permeable waterproof membrane 310 is fixedly adhered to anouter surface of the outer fabric layer 322.

Step 710: cutting the inner sleeve base material 300 into an innersleeve cut piece 23, as shown in FIGS. 5 and 6. The inner sleeve cutpiece 23 includes a fabric lining layer 231 taken from the fabric lininglayer 321, an outer fabric layer 232 taken from the outer fabric layer322, a foam layer 233 taken from the foam layer 323, and amoisture-permeable waterproof layer 234 taken from themoisture-permeable waterproof membrane 310.

Step 720: sewing the inner sleeve cut piece 23 into a shoe-shaped innersleeve 21, as shown in FIGS. 6 and 7. The shoe-shaped inner sleeve 21defines a foot space 24 having a top open end.

Step 730: fixedly connecting a plurality of waterproof strips 221 to anouter surface of the moisture-permeable waterproof layer 234 so as tocover the seams of the shoe-shaped inner sleeve 21, thereby forming ashoe-shaped inner sleeve unit 20, as shown in FIG. 8.

Step 740: sewing an upper cut piece 17 into an upper unit 10, as shownin FIGS. 9 to 12. In this embodiment, the upper cut piece 17 is made ofknitted fabric, and has a main body 18, and two wing portions 19symmetrically disposed on two opposite sides of the main body 18 andintegrally connected as one piece with the main body 18. The main body18 has a main body front convex edge 181, two symmetrical main body rearend mating edges 182, a main body rear concave edge 183 between the mainbody rear end mating edges 182 and opposite to the main body frontconvex edge 181, and two symmetrical main body rear lateral mating edges184 each of which is connected to one end of a respective one of themain body rear end mating edges 182 that is distal to the main body rearconcave edge 183. Specifically, each main body rear end mating edge 182is located between the main body rear concave edge 183 and acorresponding one of the main body rear lateral mating edges 184. Eachof the main body front convex edge 181 and the main body rear concaveedge 183 has two opposite ends.

Each wing portion 19 has a wing lateral mating edge 191 spaced apartfrom the main body 18 and having a front end and a rear end, a wingfront curved edge 192 connected between the front end of the winglateral mating edge 191 and a corresponding one of the opposite ends ofthe main body front convex edge 181, and a wing rear curved edge 193connected between the rear end of the wing lateral mating edge 191 and acorresponding one of the main body rear lateral mating edges 184.

In this embodiment, the main body rear end mating edges 182 areabuttingly connected to each other by sewing, the wing lateral matingedges 191 of the wing portions 19 are abuttingly connected to each otherby sewing, the wing front curved edges 192 of the wing portions 19 areabuttingly connected to the main body front convex edge 181 by sewing,and the wing rear curved edges 193 of the wing portions 19 arerespectively and abuttingly connected to the main body rear lateralmating edges 184 by sewing, thereby forming the upper unit 10.

The upper unit 10 defines an interior space 194 having a top open end,and includes a bottom surface 11 (see FIG. 12), and a peripheral surface12 connected to a periphery of the bottom surface 11 and cooperatingwith the same to define the interior space 194. Further, the upper unit10 has a toe stitching portion 13, a heel stitching portion 14, a bottomstitching portion 15, and a rear end stitching portion 16. The toestitching portion 13, the heel stitching portion 14 and the bottomstitching portion 15 are located on the bottom surface 11 of the upperunit 10, while the rear end stitching portion 16 is located on a rearend of the peripheral surface 12 of the upper unit 10. The toe stitchingportion 13 extends along a junction of the main body front convex edge181 and the wing front curved edges 192. The heel stitching portion 14extends along a junction of the main body rear lateral mating edges 184and the wing rear curved edges 193. The bottom stitching portion 15extends along a junction of the wing lateral mating edges 191. The rearend stitching portion 16 extends along a junction of the main body rearend mating edges 182. In this embodiment, each of the toe stitchingportion 13, the heel stitching portion 14, the bottom stitching portion15 and the rear end stitching portion 16 is formed by a single stitch,but is not limited thereto.

Step 750: sleeving the shoe-shaped inner sleeve unit 20, which ismoisture-permeable and waterproof, on a forming portion 210 of a last200 such that the forming portion 210 of the last 200 is inserted intothe foot space 24 (see FIG. 8) through the top open end thereof, asshown in FIG. 13. The forming portion 210 has a forming volume. In thisembodiment, the foot space 24 has a volume smaller than the formingvolume of the forming portion 210 by 5 to 10%. At this time, the formingportion 210 will temporarily expand the shoe-shaped inner sleeve unit20.

Step 760: coating a bonding agent 31 on an inner surface of the upperunit 10. In this embodiment, the bonding agent 31 is hot melt adhesivesprayed on the inner surface of the upper unit 10, as shown in FIG. 14.

Step 770: sleeving the upper unit 10 on an assembly of the shoe-shapedinner sleeve unit 20 and the last 200 (see FIG. 13) such that theassembly of the shoe-shaped inner sleeve unit 20 and the last 200 isinserted into the interior space 194 of the upper unit 10 through thetop open end thereof, as shown in FIG. 15. In this embodiment, theinterior space 194 has a volume smaller than the forming volume of theforming portion 210 by 5 to 10%. At this time, the forming portion 210will also temporarily expand the upper unit 10.

Step 780: placing an assembly of the upper unit 10, the shoe-shapedinner sleeve unit 20 and the last 200 in a heating device 400, as shownin FIG. 16, to heat the same to a predetermined heating temperature anda predetermined heating time. In this way, the bonding agent 31 betweenthe upper unit 10 and the shoe-shaped inner sleeve unit 20 will be curedby heating and will be formed into a first adhesive layer 30 (see FIG.24) between the inner surface of the upper unit 10 and an outer surfaceof the shoe-shaped inner sleeve unit 20, thereby fixing together theupper unit 10 and the shoe-shaped inner sleeve unit 20.

In this embodiment, the heating device 400 is an oven, the predeterminedheating temperature is between 50° C. to 150° C., and the predeterminedheating time is not less than 10 minutes.

Step 790: removing the assembly of the upper unit 10, the shoe-shapedinner sleeve unit 20 and the last 200 from the heating device 400, andthen placing the same in a vacuum bag 500, as shown in FIG. 17, afterwhich air is evacuated from the vacuum bag 500 for a predeterminedvacuum time. In this embodiment, the predetermined vacuum time isbetween 20 to 60 seconds.

Step 800: placing the vacuum bag 500, which contains the assembly of theupper unit 10, the shoe-shaped inner sleeve unit 20 and the last 200, ina freezing device 600, as shown in FIG. 18, and freezing the same to apredetermined freezing temperature and a predetermined freezing time. Inthis embodiment, the freezing device 600 is a freezer, the predeterminedfreezing temperature is between −5° C. to 5° C., and the predeterminedfreezing time is not less than 2 hours.

Step 810: removing the vacuum bag 500 containing the assembly of theupper unit 10, the shoe-shaped inner sleeve unit 20 and the last 200from the freezing device 600, and then removing the assembly of theupper unit 10, the shoe-shaped inner sleeve unit 20 and the last 200from the vacuum bag 500 by breaking the vacuum bag 500, as shown in FIG.19.

Step 820: pulling out the last 200 from the shoe-shaped inner sleeveunit 20. At this time, the upper unit 10 and the shoe-shaped innersleeve unit 20 form a three-dimensional (3D) moisture-permeablewaterproof upper structure 70, as shown in FIG. 20. In this step, sinceeach of the interior space 194 of the upper unit 10 and the foot space24 of the shoe-shaped inner sleeve 21 has a volume smaller than theforming volume of the forming portion 210 of the last 200 by 5 to 10%,after the last 200 is pulled out, each of the upper unit 10 and theshoe-shaped inner sleeve unit 20 will elastically shrink back to itsoriginal volume. As such, the 3D moisture-permeable waterproof upperstructure 70 can provide a good covering effect for a foot of a user.

Step 830: fixing two decorative tightening plates 41 to left and rightsides of a sole 50, as shown in FIG. 21. In this embodiment, eachdecorative tightening plate 41 has a bottom end portion 411 connected tothe sole 50, and a top end portion 412 formed with a plurality ofspaced-apart through holes 413.

Step 840: sleeving the 3D waterproof moisture-permeable upper structure70 on the last 200, as shown in FIG. 22.

Step 850: fixing the sole 50 to a bottom portion of the 3Dmoisture-permeable waterproof upper structure 70 such that thedecorative tightening plates 41 are located on left and right sides ofthe 3D moisture-permeable waterproof upper structure 70, as shown inFIGS. 21 and 22.

In this embodiment, an adhesive agent 61 (see FIG. 24) is used to fixtogether a top portion of the sole 50 and the bottom portion of the 3Dmoisture-permeable waterproof upper structure 70. After the adhesiveagent 61 is solidified, a second adhesive layer 60 (see FIG. 24) isformed between the top portion of the sole 50 and the bottom portion ofthe 3D moisture-permeable waterproof upper structure 70.

Step 860: pulling out the last 200 from the 3D moisture-permeablewaterproof upper structure 70, as shown in FIG. 23.

Step 870: removably threading a tightening strap 42 through the throughholes 413 in the decorative tightening plates 41 to interconnect thesame, as shown in FIG. 25. In this embodiment, the decorative tighteningplates 41 and the tightening strap 42 can be defined as a tighteningunit 40.

Thus, the making of the moisture-permeable waterproof shoe 100 iscompleted, as shown in FIGS. 25 and 26.

From the foregoing, the advantages of this disclosure can be summarizedas follows:

1) The upper cut piece 17 is sewn to directly form the 3D upper unit 10.In comparison with the prior art, the upper unit 10 of themoisture-permeable waterproof shoe 100 of this disclosure does not needto be sewn with the midsole cardboard 2 (see FIGS. 1 and 2) of the priorart, so that it is more labor-saving. Further, the number of componentsof this disclosure is minimized, so that the manufacturing cost thereofis reduced.

2) In comparison with the prior art, each of the interior space 194 ofthe upper unit 10 and the foot space 24 of the shoe-shaped inner sleeve21 of this disclosure has a volume smaller than the forming volume ofthe forming portion 210 of the last 200 by 5 to 10%, so that, after thelast 200 is pulled out from the 3D moisture-permeable waterproof upperstructure 70, the 3D moisture-permeable waterproof upper structure 70will elastically shrink back to its original volume. As such, for userswhose foot size corresponds to the size of the last 200, themoisture-permeable waterproof shoe 100 of this disclosure can provide agood covering effect, as well as comfort during wear thereof.

3) In comparison with the prior art, a bottom structure of the upperunit 10 and a bottom structure of the shoe-shaped inner sleeve unit 20are stacked under the foot of the user, and have a total thickness thatcan provide good elasticity and comfort feeling during wear of themoisture-permeable waterproof shoe 100 of this disclosure.

In summary, the moisture-permeable waterproof shoe 100 of thisdisclosure has an integrally formed upper unit 10, so that making of themoisture-permeable waterproof shoe 100 is labor saving, thereby reducingthe manufacturing cost thereof. Further, the moisture-permeablewaterproof shoe 100 has good covering and elasticity effect during wearthereof, and is also comfortable to wear. Therefore, the object of thisdisclosure can indeed be achieved.

While the disclosure has been described in connection with what isconsidered the exemplary embodiment, it is understood that thisdisclosure is not limited to the disclosed embodiment but is intended tocover various arrangements included within the spirit and scope of thebroadest interpretation so as to encompass all such modifications andequivalent arrangements.

What is claimed is:
 1. A method for making a moisture-permeablewaterproof shoe comprising: (A) sleeving a shoe-shaped inner sleeveunit, which is moisture-permeable and waterproof and which defines afoot space having a top open end, on a forming portion of a last suchthat the forming portion of the last is inserted into the foot spacethrough the top open end thereof, the forming portion having a formingvolume, the foot space having a volume smaller than the forming volumeof the forming portion by 5 to 10%; (B) coating a bonding agent on aninner surface of an upper unit which defines an interior space having atop open end; (C) sleeving the upper unit on an assembly of theshoe-shaped inner sleeve unit and the last such that the assembly of theshoe-shaped inner sleeve unit and the last is inserted into the interiorspace through the top open end thereof, the interior space having avolume smaller than the forming volume of the forming portion by 5 to10%; (D) placing an assembly of the upper unit, the shoe-shaped innersleeve unit and the last in a heating device to heat the assembly of theupper unit, the shoe-shaped inner sleeve unit and the last to apredetermined heating temperature and a predetermined heating time; (E)removing the assembly of the upper unit, the shoe-shaped inner sleeveunit and the last from the heating device, and then placing the assemblyof the upper unit, the shoe-shaped inner sleeve unit and the last in avacuum bag, after which air is evacuated from the vacuum bag for apredetermined vacuum time; (F) placing the vacuum bag, which containsthe assembly of the upper unit, the shoe-shaped inner sleeve unit andthe last, in a freezing device to freeze the vacuum bag to apredetermined freezing temperature and a predetermined freezing time;(G) removing the vacuum bag from the freezing device, and then removingthe assembly of the upper unit, the shoe-shaped inner sleeve unit andthe last from the vacuum bag; (H) pulling out the last from theshoe-shaped inner sleeve unit, the upper unit and the shoe-shaped innersleeve unit forming a three-dimensional moisture-permeable waterproofupper structure after the last is pulled out; and (I) fixing a sole to abottom portion of the three-dimensional moisture-permeable waterproofupper structure.
 2. The method as claimed in claim 1, furthercomprising, before step (A): (A1) adhering a moisture-permeablewaterproof membrane to a three-layer fabric to form an inner sleeve basematerial, the three-layer fabric including a fabric lining layer, anouter fabric layer, and a foam layer fixed between the fabric lininglayer and the outer fabric layer, the moisture-permeable waterproofmembrane being adhered to an outer surface of the outer fabric layer;(A2) cutting the inner sleeve base material into an inner sleeve cutpiece, the inner sleeve cut piece including a fabric lining layer, anouter fabric layer, a foam layer fixed between the fabric lining layerand the outer fabric layer, and a moisture-permeable waterproof layerfixed to an outer surface of the outer fabric layer; (A3) sewing theinner sleeve cut piece into a shoe-shaped inner sleeve, the shoe-shapedinner sleeve defining the foot space; and (A4) fixedly connecting aplurality of waterproof strips to an outer surface of themoisture-permeable waterproof layer so as to cover the seams of theshoe-shaped inner sleeve, thereby forming the shoe-shaped inner sleeveunit.
 3. The method as claimed in claim 2, further comprising step (A5)between step (A4) and step (A): (A5) sewing an upper cut piece into theupper unit, the upper cut piece being made of knitted fabric and havinga main body, and two wing portions symmetrically disposed on twoopposite sides of the main body and integrally connected as one piecewith the main body, the main body having a main body front convex edge,two symmetrical main body rear end mating edges, a main body rearconcave edge between the main body rear end mating edges and opposite tothe main body front convex edge, and two symmetrical main body rearlateral mating edges respectively connected to the main body rear endmating edges, each of the wing portions having a wing lateral matingedge spaced apart from the main body and having a front end and a rearend, a wing front curved edge connected between the front end of thewing lateral mating edge and a corresponding one of the opposite ends ofthe main body front convex edge, and a wing rear curved edge connectedbetween the rear end of the wing lateral mating edge and a correspondingone of the main body rear lateral mating edges; wherein, the main bodyrear end mating edges are abuttingly connected to each other by sewing,the wing lateral mating edges of the wing portions are abuttinglyconnected to each other by sewing, the wing front curved edges of thewing portions are abuttingly connected to the main body front convexedge by sewing, and the wing rear curved edges of the wing portions arerespectively and abuttingly connected to the main body rear lateralmating edges by sewing, thereby forming the upper unit; and wherein theupper unit includes a bottom surface, and a peripheral surface connectedto a periphery of said bottom surface and cooperating with the bottomsurface to define the interior space, the upper unit having a toestitching portion extending along a junction of the main body frontconvex edge and the wing front curved edges, and a heel stitchingportion extending along a junction of the main body rear lateral matingedges and the wing rear curved edges, the toe stitching portion and theheel stitching portion being located on the bottom surface of the upperunit.
 4. The method as claimed in claim 3, wherein, in step (A5), theupper unit further has a bottom stitching portion extending along ajunction of the wing lateral mating edges and located on the bottomsurface of the upper unit, and a rear end stitching portion extendingalong a junction of the main body rear end mating edges and located on arear end of the peripheral surface of the upper unit.
 5. The method asclaimed in claim 1, further comprising step (I1) between step (H) andstep (I), in which two decorative tightening plates are fixed to leftand right sides of the sole.
 6. The method as claimed in claim 5,further comprising step (I2) between step (I) and step (I1), in whichthe three-dimensional waterproof moisture-permeable upper structure issleeved on the last.
 7. The method as claimed in claim 6, wherein instep (I1), each of the decorative tightening plates having a bottom endportion connected to the sole, and a top end portion formed with aplurality of spaced-apart through holes.
 8. The method as claimed inclaim 7, further comprising, after step (I): (J) pulling out the lastfrom the three-dimensional moisture-permeable waterproof upperstructure; and (K) removably threading a tightening strap through thethrough holes in the tightening plates to interconnect the decorativetightening plates.
 9. The method as claimed in claim 1, wherein: in step(B), the bonding agent is hot melt adhesive sprayed on the inner surfaceof the upper unit; in step (D), the predetermined heating temperature isbetween 50° C. to 150° C., and the predetermined heating time is notless than 10 minutes; in step (E), the predetermined vacuum time isbetween 20 to 60 seconds; and in step (F), the predetermined freezingtemperature is between −5° C. to 5° C., and the predetermined freezingtime is not less than 2 hours.
 10. The method as claimed in claim 9,wherein, in step (D), the heating device is an oven, and in step (F),the freezing device is a freezer.